Murray Walk behind mower, Model # 20705X6M 5.5 Briggs & \St not getting gas, I have torn the carburator of three times replaced gasgets needle valve cleaned all ports throughly, checked passage of gas with needle type air compressor good air flow,,primed and primed can hear air primer appears to work but no gas. Cant find owners manual on line please advise

Clean ALL the very small holes in the brass bolt that holds the carb bowl on.Some are VERY small and easily clogged. With bowl off and the bowl float hanging free, does gas readily flow? It should, and it should of course stop when the float is raised (putting the needle valve on its seat). If this event is occuring, then the main jet must be badly clogged. If no gas even gets into the bow. (not enough details).. then there is a vacuum lock or something strange going on in the fuel tank (cap). The threads of the fuel cap on a mower allow it to vent, preventing vacuum lock of the fuel flow.Start at the tank and go back in. Please repost as this is a good one.